Thank you for your interest! "Introduction to Functions" by Hanzo Takeuchi "Theory of Functions" edited by Hisami Nishigaki, Masae Orihara "General Theory of Functions" by Eisaku Yamazaki These are three physics (function) textbooks published in the 1950s and 60s. They have only been stored on a bookshelf, so their condition is not good. They feel very old... Please purchase only if you understand this. #physics #oldbooks #usedbooks #functions #Showa